Tim, I think Zimmerman is an idiot for carrying a gun. I suspect Trayvon went after him, and was kicking his butt 'a little'. Certainly not enough to be shot and killed by what us layman should consider good decision making, but quite possibly enough that a legal standard of self defense will not be beyond reasonable doubt. I wouldn't rule out a legit struggle for the exposed weapon either. I didn't respond to TF02 last night because he's right. Zimmerman ruined his own life even if he acted within the law. Even if he was in danger of grave bodily harm or death, pulling that trigger ruined his life. He may have had no choice. We don't know.

All except, he is a idiot for carrying.
As most in the thread will know by now, I carry and am an advocate for the right to carry. However, I am for stricter gun laws on who should be able to own a firearm and carry. A simple background check will not do, IMO. In most southern states, people can trade and sell weapons without transfer from a dealer and it does not need to be registered.
At the moment Zimmerman thought his life was in danger, if he decided to shoot at that time, he has a right to protect himself. However, with that decision he has to know that in doing so he will first and most importantly, take the life of another person, and 2. live with it.
I have not had time to keep up, with the voice recognition on the 911 calls. Did someone scream "no" before the shot? I hear the "help" and there is conflicting reports that it may or may not be Zimmerman. If there is a "no", who actually says "no" before the shot would be a huge indicator for me as to who had clear control of the gun and the intentions of the person who yelled "no". If Zimmerman yells "no" I would imagine (speculation) Martin sees the gun and goes for it. If Martin yells "no" Zimmerman controls the gun and Martin may at that time concede the fight. Zimmerman decides to shoot anyway.
We don't know if Zimmerman really felt his life was in danger, or if there was a struggle for the exposed gun. If Zimmerman gained clear control of the gun in a struggle and decided to shoot at that time, he should be in jail because he did not feel the need to use the gun when Martin was on top of him. If Martin and Zimmerman were both still going after the gun and the gun went off it could be an accidental shooting.
We don't have a report of the actual events of the shot and details about the gun are not being released. However, I did find this.
The handgun that killed Trayvon Martin, an unarmed black 17-year-old, was fired once — not twice — by a neighborhood crime watch volunteer, according to information obtained by the Orlando Sentinel.
Police found a single shell casing at the scene, and when they seized George Zimmerman's handgun, a Kel Tel 9 mm, its magazine was full, according to a source close to the investigation. The only bullet missing was the one in the chamber, the source said.
http://www.palmbeachpost.com/news/crime/trayvon-martin-shooting-gun-that-killed-teen-was-2248283.html?printArticle=yThis means a bullet was not chambered after the initial shot or the magazine would not be full and a bullet would be in the chamber. This would indicate that the gun jams during the altercation. This to me is possible proof of a struggle for the gun and a possible accidental shot which Zimmerman claims self defense. Remember, we have not heard an official report from Zimmerman himself. He may say this is what happened.